<?php
//dezend by http://www.yunlu99.com/ QQ:270656184
class CI_DB_Cache
{
	/**
	 * CI Singleton
	 *
	 * @var	object
	 */
	public $CI;
	/**
	 * Database object
	 *
	 * Allows passing of DB object so that multiple database connections
	 * and returned DB objects can be supported.
	 *
	 * @var	object
	 */
	public $db;

	public function __construct(&$db)
	{
		$this->CI = &get_instance();
		$this->db = &$db;
		$this->CI->load->helper('file');
		$this->check_path();
	}

	public function check_path($path = '')
	{
		if ($path === '') {
			if ($this->db->cachedir === '') {
				return $this->db->cache_off();
			}

			$path = $this->db->cachedir;
		}

		$path = (realpath($path) ? rtrim(realpath($path), DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR : rtrim($path, '/') . '/');

		if (!is_dir($path)) {
			log_message('debug', 'DB cache path error: ' . $path);
			return $this->db->cache_off();
		}

		if (!is_really_writable($path)) {
			log_message('debug', 'DB cache dir not writable: ' . $path);
			return $this->db->cache_off();
		}

		$this->db->cachedir = $path;
		return true;
	}

	public function read($sql)
	{
		$segment_one = ($this->CI->uri->segment(1) == false ? 'default' : $this->CI->uri->segment(1));
		$segment_two = ($this->CI->uri->segment(2) == false ? 'index' : $this->CI->uri->segment(2));
		$filepath = $this->db->cachedir . $segment_one . '+' . $segment_two . '/' . md5($sql);

		if (false === ($cachedata = @file_get_contents($filepath))) {
			return false;
		}

		return unserialize($cachedata);
	}

	public function write($sql, $object)
	{
		$segment_one = ($this->CI->uri->segment(1) == false ? 'default' : $this->CI->uri->segment(1));
		$segment_two = ($this->CI->uri->segment(2) == false ? 'index' : $this->CI->uri->segment(2));
		$dir_path = $this->db->cachedir . $segment_one . '+' . $segment_two . '/';
		$filename = md5($sql);
		if (!is_dir($dir_path) && !@mkdir($dir_path, 488)) {
			return false;
		}

		if (write_file($dir_path . $filename, serialize($object)) === false) {
			return false;
		}

		chmod($dir_path . $filename, 416);
		return true;
	}

	public function delete($segment_one = '', $segment_two = '')
	{
		if ($segment_one === '') {
			$segment_one = ($this->CI->uri->segment(1) == false ? 'default' : $this->CI->uri->segment(1));
		}

		if ($segment_two === '') {
			$segment_two = ($this->CI->uri->segment(2) == false ? 'index' : $this->CI->uri->segment(2));
		}

		$dir_path = $this->db->cachedir . $segment_one . '+' . $segment_two . '/';
		delete_files($dir_path, true);
	}

	public function delete_all()
	{
		delete_files($this->db->cachedir, true, true);
	}
}

defined('BASEPATH') || exit('No direct script access allowed');

?>
